Method and system for detecting connection fault of parallel connection cells

ABSTRACT

Disclosed is a method and system for detecting connection failure of a parallel connection cell, and for a battery that is being discharged by the operation of an external device, by detecting whether there is a section matching the amount of change in the discharge voltage value when a cell connection failure condition occurs due to a pre-prepared current interruption device (CID) operation or an open parallel connection line from the change in the discharge voltage value of the battery being discharged.

TECHNICAL FIELD

The present invention relates to a method and system for detectingconnection failure of a parallel connection cell, and more specifically,to a method and system for detecting connection failure of a parallelconnection, which are capable of detecting a disconnection of a specificcell due to an open parallel connection line of a cell or an operationof a protection element such as a CID.

BACKGROUND ART

Unlike primary batteries that cannot be recharged, rechargeablesecondary batteries are widely used in various fields ranging fromelectric bicycles, electric vehicles, and energy storage systems (ESS)as well as small high-tech electronic devices such as smart phones,notebook computers, and tablet PCs.

Because medium and large devices such as electric bicycles, electricvehicles, and energy storage systems (ESS) require high power and largecapacity, when the secondary battery is applied to medium and largedevices, a plurality of battery cells are directly/parallel connected touse battery packs electrically connected to each other.

In general, battery cells included in battery packs are protectionelements to ensure safety during charging and are equipped with acurrent interruption device (CID) that cuts off when the pressure insidethe cell increases to prevent current from flowing through the cell, sothat they are configured to safely prevent overcharging of the battery.

However, if the CID of a specific battery cell operates while thebattery cells are connected in parallel, since the connection of thecorresponding failure battery cell is disconnected, overcurrent flows inthe remaining normal battery cells parallel connected with the failurebattery cell by the current flowing through the failure battery cell, sothat overloading occurs on normal battery cells. In addition, even whendisconnection of a specific battery cell occurs among parallel connectedbattery cells due to a cause such as opening of the parallel connectionline of a specific battery cell in addition to the operation of theprotection element such as CID as above, overcurrent flows through theremaining normal battery cells.

Such a phenomenon promotes cell deterioration and causes a decrease inbattery performance and lifespan, in order to prevent this problem fromoccurring, there is a need for a technology capable of detecting a celldisconnection due to an open parallel connection line or a CID operationwhen a plurality of battery cells are connected in parallel.

-   (Patent Document 1) KR10-2017-0068608 A1

DISCLOSURE Technical Problem

The present invention is to solve the above-described problem, and anobject of the present invention is to provide a method of detecting adisconnection due to an open parallel connection line of a specific cellamong parallel connected battery cells or a CID operation.

Technical Solution

According to an embodiment of the present invention, a method ofdetecting connection failure of a parallel connection cell includes: areference data acquisition step of acquiring reference data when a cellconnection failure occurs by generating a current interruption device(CID) operation or a parallel connection line open condition in abattery being discharged; a monitoring step of monitoring actual drivingdischarge data generated on the battery being discharged by an operationof an external device; and a cell connection failure detection step ofcomparing, from an actual driving discharge data monitored in themonitoring step, whether there is a section matching the amount ofchange in the discharge voltage value due to a CID operation or an openparallel connection line in the reference data and detecting whether acell connection failure occurs due to the CID operation or the openparallel connection line in the corresponding battery according to acomparison result.

Moreover, the method further includes an abnormality notification stepfor generating and notifying an abnormality signal when it is detectedthat the battery is in a state in which cell connection failure occursdue to the CID operation or the open parallel connection line in thecell connection failure detection step.

In more detail, the reference data acquisition step includes: a drivingdischarge reference data acquisition step of measuring a dischargevoltage value at a predetermined periodic interval while discharging apredetermined reference battery connected to an external device throughan operation of the external device, and acquiring driving dischargereference data based on the measured discharge voltage value; aconnection failure time point reference data acquisition step ofacquiring connection failure time point reference data generatedaccordingly due to a CID operation or an open parallel connection lineat a predetermined time point while the driving discharge reference dataacquisition step is in progress; a first connection failure detectiondata acquisition step of summing the acquired driving dischargereference data and connection failure time point reference data for thesame time interval and first acquiring data on a change in a dischargevoltage value in a CID operation or an open area of a parallelconnection line; and a final connection failure detection reference dataacquisition step of repeating the driving discharge reference dataacquisition step, the connection failure time point reference dataacquisition step, and the first connection failure detection referencedata acquisition step a predetermined number of times or more and byapplying a machine learning technique to a plurality of first connectionfailure detection reference data obtained through this, finallyacquiring data on the amount of change in the discharge voltage value inthe CID operation or the parallel connection line open area.

Moreover, the cell connection failure detection step includes: a matchcomparison step of comparing whether a section matching the finalconnection failure detection reference data acquired in the finalconnection failure detection reference data acquisition step exists fromthe actual driving discharge data monitored in the monitoring step; anda connection failure determination step of determining, from the actualdriving discharge data as a result of the comparison, the correspondingsection as the section in which the amount of change in the dischargevoltage value occurs due to the CID operation or the open parallelconnection line when there is the section matching the final connectionfailure detection reference data and determining that the cellconnection failure occurs due to the CID operation or the open parallelconnection line in the corresponding battery.

Here, wherein the driving discharge reference data is a change amount ofa discharge voltage value for the reference battery, wherein theconnection failure time point reference data is an amount of change in adischarge voltage value caused by a CID operation or an open parallelconnection line with respect to the reference battery.

According to an embodiment of the present invention, a connectionfailure detection system of a parallel connection cell includes: one ormore batteries including at least one or more cells connected inparallel; a voltage measurement unit configured to measure a dischargevoltage of a battery at predetermined periodic intervals; a monitoringunit configured to monitor actual driving discharge data derived as ananalog signal in a waveform form based on the discharge voltage valuemeasured by the voltage measuring unit; a memory unit configured tostore reference data for detecting whether a cell connection failureoccurs due to a current interruption device (CID) operation or an openparallel connection line in the battery; and a cell connection failuredetection unit configured to detect whether there is a section matchingthe amount of change in the discharge voltage value due to a CIDoperation or an open parallel connection line in the actual drivingdischarge data monitored by the monitoring unit using the reference datastored in the memory unit and detecting whether a cell connectionfailure occurs due to the CID operation or the open parallel connectionline in the corresponding battery.

Here, the reference data stored in the memory unit is configured toinclude final connection failure detection reference data, wherein thefinal connection failure detection reference data is the amount ofchange in the discharge voltage value of the battery that occurs whenthe CID operates or the parallel connection line is opened.

Furthermore, the cell connection failure detection unit includes: amatch comparison unit configured to compare whether a section matchingthe final connection failure detection data exists among actual drivingdischarge data of the battery monitored by the monitoring unit; aconnection failure determination unit configured to, as a result of thecomparison, when there is a section matching the final connectionfailure detection data in the actual driving discharge data, detect thisas a section in which the amount of change in the discharge voltagevalue occurs due to the CID operation or the open parallel connectionline open and determine whether a cell connection failure occurs due tothe CID operation or the open parallel connection line open in thecorresponding battery; and a cell connection failure detection signalgeneration unit configured to, if the connection failure determinationunit determines that the cell connection failure occurs due to the CIDoperation or the open parallel connection line in the correspondingbattery, generate and output a cell connection failure detection signalindicating this.

Moreover, the system further includes a notification unit configured togenerate and output an abnormality signal when a cell connection failuredetection signal is outputted from the cell connection failure detectionsignal generation unit of the cell connection failure detection unit.

Here, the actual driving discharge data is the amount of change in thedischarge voltage value.

Advantageous Effects

For a battery that is discharging according to an operation of anexternal device (e.g., a vehicle), the present invention can detect acell connection failure state due to a CID operation or an open parallelconnection line in real time. Therefore, in order to deal with the aboveeasily, it is possible to prevent battery deterioration and performancedegradation problems that may be caused by failure of a specific celldue to CID operation or open parallel connection line.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of an analog signal in awaveform form according to a change in a discharge voltage valuegenerated for a battery being discharged according to the operation of avehicle.

FIG. 2 is a diagram illustrating an example in which the analog signalin the waveform form shown in FIG. 1 is converted into a linear functionform.

FIG. 3 is a diagram schematically showing a principle of acquiringreference data capable of detecting a CID operation or an open state ofa parallel connection line from an analog signal in a waveform form.

FIG. 4 is a flowchart illustrating a method of detecting connectionfailure of a parallel connection cell according to the presentinvention.

FIG. 5 is a block diagram schematically showing a system for detectingconnection failure of a parallel connection cell according to thepresent invention.

BEST MODE

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings so that those ofordinary skill in the art may easily implement the present invention.However, the present invention may be implemented in various forms andis not limited to the embodiments described herein. In the drawings,parts irrelevant to the description are omitted in order to clearlydescribe the present invention, and like reference numerals refer tolike elements throughout the specification.

Hereinafter, the present invention will be described in detail withreference to the drawings.

1. Terms Used in Present Invention

A. Reference Battery/Actual Battery

The battery in the present invention has a structure in which at leastone or more cells are connected in parallel, and for example, may beinstalled and used in any device that uses batteries, includingautomobiles, scooters, electric kickboards, and energy storage systems(ESS). In this specification, a vehicle battery mounted on a vehicle andsupplying power to a power motor will be described as an example.

The reference battery used in the present invention refers to a batteryused in an experiment process of acquiring reference data for detectinga CID operation or an open state of a parallel connection line, and theactual battery refers to a battery mounted in an actual vehicle.

These are merely classified terms for convenience of description of theprocedure of the present invention, and the structure and function arethe same.

B. Driving Discharge Reference Data/Connection Failure Time PointReference Data

The driving discharge reference data is an amount of change in adischarge voltage value obtained with respect to a battery beingdischarged through a predetermined experiment, which means change valuesin a discharge voltage value represented by an analog signal in awaveform shape as shown in FIG. 1.

The connection failure time point reference data is the amount of changein the discharge voltage value that occurs when a CID operation isperformed or a parallel connection line is opened, which is acquiredthrough a predetermined experiment, and this refers to the amount ofchange in the discharge voltage value in the area A, which occurs whenthe CID operation is performed or the parallel connection line is openedamong the change values of the discharge voltage value shown in the formof a linear function as shown in FIG. 2.

C. Actual Driving Discharge Data

The actual driving discharge data is an amount of change in a dischargevoltage value obtained with respect to a battery being dischargedaccording to an actual driving of a vehicle, which means change valuesin the discharge voltage value represented by an analog signal in awaveform shape as shown in FIG. 1.

The driving discharge reference data and the actual driving dischargedata described above are terms to distinguish the amount of change inthe discharge voltage value acquired in the course of a predeterminedexperiment conducted to prepare reference data from the amount of changein the discharge voltage value acquired according to the actual vehicleoperation. These data are derived as, for example, analog signals in theform of a dynamic waveform as shown in FIG. 1.

D. External Device

The external device referred to in the present invention is a deviceequipped with a power motor and means, for example, a vehicle. However,the present invention is not limited thereto, and the external devicemay be any device using a battery such as an energy storage system(ESS), a scooter, and an electric kickboard as well as a vehicle.

2. Method for Detecting Failure of a Parallel Connection Cell Accordingto Present Invention (See FIG. 4)

The method of detecting the failure of a parallel connection cellaccording to the present invention includes the following steps.

2.1. Reference Data Acquisition Step (S100)

The reference data acquisition step is a step of acquiring referencedata when a cell connection failure occurs by generating a CID operationor a parallel connection line open situation in a battery beingdischarged, and may include the following detailed steps.

A. Driving Discharge Reference Data Acquisition Step (S110)

This is a step of acquiring driving discharge reference data of thereference battery, that is, a change in the discharge voltage value,generated according to the operation while the external device isarbitrarily operated while a predetermined reference battery is mountedon the external device.

As described above, the battery in the present invention is, forexample, a vehicle battery mounted on a vehicle to supply power to apower motor, and the external device may mean a vehicle having a powermotor. In the case of a vehicle battery, discharging is a state in whichpower is supplied to the electric motor of the vehicle, and thisdynamically changes the degree of power supplied from the battery to theelectric motor according to the style of stepping on the vehicle'saccelerator. Therefore, as shown in FIG. 1, the discharge voltage valueis derived as a decreasing waveform with various widths of change.

In other words, the driving discharge reference data acquisition step isto acquire the amount of change in the discharge voltage value derivedas an analog signal in the form of a waveform as shown in FIG. 1, andfor this, by discharging a reference battery composed of parallelconnected cells while mounted on an external device and measuring thedischarge voltage at predetermined periodic intervals, driving dischargereference data as a change amount over time may be obtained based on themeasured discharge voltage values.

B. Connection Failure Time Point Reference Data Acquisition Step (S120)

The connection failure time point reference data acquisition step is astep of acquiring a change in a discharge voltage value that occurs incase of a cell connection failure state by generating a currentinterruption device (CID) operation or a parallel connection line opensituation in any one cell while the driving discharge reference dataacquisition step S110 is in progress.

As described above, when the battery is discharged by the operation ofan external device (e.g., vehicle), since the degree to which power issupplied to the electric motor varies depending on the style of steppingon the accelerator, the change in the discharge voltage value of thebattery may be derived as an analog signal in the form of a waveform asshown in FIG. 1. If selecting and taking the median or average value ofthe corresponding discharge voltage for each detailed section for theseanalog signals, the analog signal in the form of a waveform of FIG. 1may be converted into a form of a decreasing linear function as shown inFIG. 2. In this state, when the CID of any one cell is operated or aspecific parallel connection line is opened so that a cell connectionfailure state occurs, an area where the amount of change in thedischarge voltage value decreases occurs, and the corresponding area isshown in the form of a step as shown in area A of FIG. 2. Here, it issufficient to describe the detailed section as a time section capable ofdetecting the CID operation or the open state of the parallel connectionline.

Since the discharge voltage values dynamically change in the analogsignal in the waveform form as shown in FIG. 1, even if there is an areacorresponding to the amount of change as in area A of FIG. 2, it is verydifficult to detect whether the change is due to a CID operation or anopen parallel connection line but as shown in FIG. 2, in the form of alinear function, area A can be easily distinguished.

By using these points, the connection failure time point reference dataacquisition step artificially may operate the CID of any one cell at apredetermined time point or open a specific parallel connection line tomake a cell connection failure state, and obtain the amount of change inthe discharge voltage value generated according thereto, for example,for a reference battery that is discharging, in order to obtain theamount of change in the discharge voltage value that occurs according toa connection failure due to a CID operation corresponding to area A ofFIG. 2 or an open parallel connection line. The connection failure timepoint obtained as described above, that is, the amount of change in thedischarge voltage value corresponding to area A of FIG. 2, may bereferred to as connection failure time point reference data.

C. First Connection Failure Detection Reference Data Acquisition Step(S130)

In the first connection failure detection reference data acquisitionstep, the driving discharge reference data acquired in the drivingdischarge reference data acquisition step S110 and the connectionfailure time point reference data acquired in the connection failuretime point reference data acquisition step S120 are summed for the sametime interval, and thus, in the amount of change in the dischargevoltage value that occurs according to the actual vehicle operationderived from the analog signal in the waveform form shown in FIG. 1,data capable of detecting whether a change in a discharge voltage valueoccurs due to a CID operation or a parallel connection line open may beobtained first.

In other words, by summing the data for area A shown in FIG. 2 to theanalog signal in the waveform form of FIG. 1 for the same time period,through this, as shown in FIG. 3, the amount of change in the dischargevoltage value corresponding to area B is first obtained.

As described above, the first data obtained for area B may be referredto as first connection failure time point reference data and described.

D. Final Connection Failure Detection Reference Data Acquisition Step(S140)

The final connection failure detection reference data acquisition stepmay acquire a plurality of first connection failure time point referencedata, which is the amount of change in the discharge voltage valuecorresponding to area B of FIG. 3, by repeating the above-describeddriving discharge data acquisition step S110, connection failure timepoint reference data acquisition step S120, and first connection failuredetection reference data acquisition step S130 a plurality of times, andfinally obtain data (final connection failure detection reference data)on the amount of change in the discharge voltage value corresponding toarea B of FIG. 3 by applying a machine learning technique to theobtained plurality of first connection failure time point referencedata.

On the other hand, since the discharge voltage value of the batterygenerated according to the actual operation of the vehicle is differentbecause the driving style is different for each user (driver), the rangeof the amount of change in the discharge voltage value generatedaccordingly will be very diverse. Thus, even if the change of thedischarge voltage value is derived from various examples according tovarious driving styles, in order to detect the amount of change in thedischarge voltage value caused by connection failure due to a CIDoperation or an open parallel connection line, by repeating S110 to S130to acquire a number of data according to various cases and applyingmachine learning techniques to derive reference values for a largenumber of data, this is done by learning the amount of change in area Bof FIG. 3 to obtain final connection failure detection data. Therefore,during an actual vehicle operation, a battery in which a cell connectionfailure due to a CID operation or an open parallel connection line amongbatteries mounted therein can be detected in real time.

The final connection failure detection reference data obtained asdescribed above is used as reference data that is stored in the memoryunit 400 to be described later to enable real-time detection of whethera connection failure occurs due to a CID operation or an open parallelconnection line.

2.2. Monitoring Step (S200)

The monitoring step is a step of measuring a discharge voltage valueaccording to an operation of the external device at predeterminedperiodic intervals for a battery mounted on an external device (e.g.,vehicle) during the discharging of the external device, and monitoring achange amount based on the measured discharge voltage value.

That is, the amount of change in the discharge voltage value derivedfrom the analog signal in the waveform form as shown in FIG. 1 ismonitored, and the amount of change in the discharge voltage value isreferred to as actual driving discharge data.

This step is performed by a monitoring unit 300 to be described later.

2.3. Cell Connection Failure Detection Step (S300)

The cell connection failure detection step is a step of detecting inreal time whether a change in the discharge voltage value correspondingto the cell connection failure state (final connection failure detectiondata) occurs by a CID operation or an open parallel connection lineacquired in the final connection failure reference data acquisition stepS140 to detect a cell connection failure state by the CID operation orthe open parallel connection line, from the actual driving dischargedata derived as an analog signal in the form of a waveform monitored inthe monitoring step S200, and may be configured to include the followingdetailed steps. (cell connection failure detection unit 500)

A. Match Comparison Step (S310)

The match comparison step is a step of comparing whether there is asection matching the final connection failure detection reference dataacquired in the final connection failure detection reference dataacquisition step S140 of the reference data acquisition step S100 fromthe actual driving discharge data monitored in the monitoring step S200.

That is, in the actual battery being discharged according to theoperation of an external device (e.g., vehicle), the form in which thedischarge voltage value changes is derived as an analog signal in theform of a waveform as shown in FIG. 1, and it is compared whether thereis a section matching the amount of change in the discharge voltagevalue in area B of FIG. 3 corresponding to the final connection failuredetection reference data in the waveforms having various widths ofchange. This step is performed by the match comparison unit 510described later.

B. Connection Failure Determination Step (S320)

As a result of that comparison, in the actual driving discharge datathat occurs for the actual battery currently being discharged, whenthere is a section matching the final connection failure detectionreference data, the corresponding section is determined as the sectionin which the amount of change in the discharge voltage value decreasesdue to the CID operation of at least one cell of the actual battery orthe opening of the parallel connection line, so that a cell connectionfailure detection signal for the actual battery may be generated andoutputted.

That is, in a state in which the discharge voltage value dynamicallychanges in the form of a waveform as shown in FIG. 1, when a sectionmatching the amount of change in the discharge voltage valuecorresponding to area B of FIG. 3 is detected, the corresponding sectionis determined as a section in which the amount of change in thedischarge voltage value decreases due to the operation of the CID of atleast one cell of the actual battery or the opening of a specificparallel connection line to generate and output a cell connectionfailure detection signal for the actual battery indicating thisdetermination. This step is performed by a connection failuredetermination unit 520 and a cell connection failure detection signalgeneration unit 530 described later.

Embodiment 1: When Detecting Battery Bank

Here, the cell connection failure first detection signal may include abank identification number for identifying a battery bank to which acorresponding actual battery belongs. At this time, the battery bank isa group of cells composed of a plurality of actual batteries, and abattery bank including an actual battery (cell) in which a CID operatesor a parallel connection line is opened may be detected using the bankidentification number included in the cell connection failure firstdetection signal.

Embodiment 2: When Detecting Battery Cell

As another embodiment, the cell connection failure detection signal mayinclude a battery identification number to identify a correspondingactual battery.

On the other hand, if there is no section in the actual drivingdischarge data matching the final connection failure detection referencedata, the corresponding battery may determine that the cell connectionis in a normal state in which the cell connection failure state due tothe CID operation or the open parallel connection line open does notoccur (S330).

2.4. Abnormality Notification Step (S400)

In the abnormality notification step, when a cell connection failuredetection signal is outputted in the cell connection failure detectionstep S300, an abnormality signal indicating that a cell connectionfailure occurs due to a CID operation or an open parallel connectionline to the corresponding actual battery may be generated and outputted.This is performed by the abnormality notification unit 400

Accordingly, the user can recognize and respond to an abnormality in theconnection state of the battery in real time while the external device(e.g., vehicle) is running.

Here, the abnormality signal may include an identification number of abattery bank including a battery in which a cell connection failureoccurs due to a CID operation or an open parallel connection line open,or a corresponding battery.

2.5. Cell Connection Failure Final Detection Data Feedback Step (S500)

Data (change amount of the discharge voltage value) on the connectionfailure state of the cell acquired and determined in the cell connectionfailure detection step S300 is fed back to the final connection failuredetection reference data acquisition step S140 of the reference dataacquisition step S100, so that reference data by machine learning can beenriched and enhanced.

If the above reference data acquisition step S100 is a process ofacquiring reference data by artificially generating a cell connectionfailure state, the data in case of cell connection failure in actualsituation is fed back to reference data through this feedback step, sothat reference data can be obtained more precisely.

Accordingly, conventionally, since the analog signal generated while thevehicle battery is discharging is a complex waveform that includes boththe discharge voltage values that dynamically change and the dischargevoltage values that change accordingly when the CID operates or theparallel connection line is opened, from there, it is difficult todetect the area corresponding to the amount of change in the dischargevoltage value due to the CID operation or the open parallel connectionline, making it difficult to detect the cell connection failure(disconnection), so that for this reason, there is a problem ofpromoting cell degeneration. In contrast, the present invention obtainsdata on the amount of change in the discharge voltage value generatedwhen the CID operates or the parallel connection line is opened throughthe above-described experiment, and by using this, it is possible todetect an area corresponding to the amount of change in the dischargevoltage value due to the CID operation or the open parallel connectionline from the analog signal in the form of a complex waveform generatedduring discharge. Accordingly, it is possible to detect in real time astate of cell connection failure occurring with respect to the batterybeing discharged. Therefore, in order to deal with the above easily, itis possible to prevent battery deterioration and performance degradationproblems that may be caused by failure of a specific cell due to CIDoperation or open parallel connection line.

3. Connection Failure Detection System of Parallel Connection CellAccording to Present Invention (See FIG. 5)

3.1. Battery 100

The connection failure detection system of a parallel connection cellaccording to the present invention may be configured to include one ormore batteries configured to include one or more battery cells 110, andthe battery cells are connected in parallel, such that electricalconnection between the battery cells is made.

The battery may be, for example, a battery mounted and used in devicessuch as a vehicle, an energy storage system (ESS), a scooter, and anelectric kickboard, and in this specification, a vehicle battery mountedon a vehicle and supplying power to an electric motor will be describedas an example.

3.2. Voltage Measurement Unit 200

The voltage measurement unit is configured to measure a dischargevoltage value of the battery at a predetermined periodic interval, andmay acquire actual driving discharge data, which is a change in thedischarge voltage value of the battery, based on the discharge voltagevalue measured by the voltage measurement unit.

3.3. Monitoring Unit 300

The monitoring unit is configured to monitor the amount of change in thedischarge voltage value of the battery derived as an analog signal inthe form of a waveform as shown in FIG. 1 based on the discharge voltagevalue measured by the voltage measurement unit 200 at a predeterminedperiodic interval.

In the case of vehicle batteries, the degree of supplying power to theelectric motor varies depending on the style of stepping on theaccelerator, the amount of change in the discharge voltage value of thebattery may be derived as an analog signal in the form of a waveform ofFIG. 1, and the monitoring unit monitors the amount of change in thedischarge voltage value (actual driving discharge data) in real time.

3.4. Memory Unit 400

This is a component in which reference data is stored to detect a cellconnection failure state due to a CID operation or an open parallelconnection line obtained through a predetermined experiment.

The reference data includes final connection failure detection referencedata as an amount of change in a discharge voltage value caused by a CIDoperation or an open parallel connection line, and in simple terms,means the amount of change in the discharge voltage value correspondingto area B of FIG. 3.

When explaining the process of obtaining the final connection failuredetection reference data stored in the memory unit, first, with apredetermined battery mounted on an external device (e.g., vehicle),while artificially operating the external device, a driving dischargereference data of a battery discharge voltage generated according to theoperation is obtained. The battery in the present invention is, forexample, a vehicle battery that is mounted on a vehicle and suppliespower to a power motor. In the case of a vehicle battery, sincedischarging is a state in which power is supplied to the electric motorof the vehicle, and this dynamically changes the degree of powersupplied from the battery to the electric motor according to the styleof stepping on the vehicle's accelerator, as shown in FIG. 1, thedischarge voltage value has various widths and is derived as adecreasing waveform.

In the process of acquiring driving discharge reference data derived inthis form, by generating a CID operation or a specific parallelconnection line open situation in any one cell, the amount of change(connection failure time point reference data) in the discharge voltagevalue that occurs in case of cell connection failure is obtained. Thereason for doing this process is that as described above, when thebattery is discharged according to the operation of the electricvehicle, since the degree to which power is supplied to the electricmotor varies depending on the style of stepping on the accelerator, thechange in the discharge voltage value of the battery may be derived asan analog signal in the form of a waveform as shown in FIG. 1. Ifselecting and taking the median or average value of the correspondingdischarge voltage for each detailed section for these analog signals, itwas confirmed that the analog signal in the form of a waveform of FIG. 1may be converted into a form of a decreasing linear function as shown inFIG. 2. In addition, In this state, when the CID of any one cell isoperated or a specific parallel connection line is opened so that a cellconnection failure state occurs, it was confirmed that an area where theamount of change in the discharge voltage value decreases occurs, andthe corresponding area is shown in the form of a step as shown in area Aof FIG. 2. Since the discharge voltage values dynamically change in theanalog signal in the waveform form as shown in FIG. 1, even if the sameamount of change as in area A of FIG. 2 occurs, it is very difficult todetect whether the change is due to a CID operation or an open parallelconnection line but as shown in FIG. 2, in the form of a linearfunction, area A is easily distinguished.

By using these points, in order to obtain the amount of change in thedischarge voltage value for area A of FIG. 2, for example, for a batterythat is being discharged, the CID of any one cell is operated at apredetermined time point or a specific parallel connection line isopened to artificially cause cell connection failure, and the resultingchange (connection failure time point reference data) in the dischargevoltage value is acquired.

When actual driving discharge data and connection failure time pointreference data are obtained through the above-described process, thedata is summed over the same time interval, and reference data capableof detecting whether there is a change in a discharge voltage valueoccurring due to a CID operation or an open parallel connection line maybe obtained first from the amount of change in the discharge voltagevalue derived from the analog signal in the waveform form shown inFIG. 1. In simple terms, the amount of change in the discharge voltagevalue in area A shown in FIG. 2 is added to the analog signal in thewaveform form of FIG. 1 for the same time period, and the amount ofchange in the discharge voltage value corresponding to area B shown inFIG. 3 is first obtained.

By repeating a number of such processes, a number of data on the amountof change corresponding to area B of FIG. 3 may be obtained, and byapplying a machine learning technique to these data and learning aboutthe change in the discharge voltage value due to CID operation orparallel connection line open, final connection failure detectionreference data for detecting a change amount for a CID operation or aparallel connection line open time point may be obtained from an analogsignal.

On the other hand, the memory unit may receive feedback of failuredetection data of a battery, which is detected as a cell connectionfailure due to a CID operation or an open parallel connection line fromthe cell connection failure detection unit 500 to be described later andreflect the feedback to the reference data and store the reflected data.As described above, since the reference data previously stored in thememory unit is data acquired by artificially generating a cellconnection failure state, by receiving feedback of the data (failuredetection data) from the cell connection failure detection unit 500 andreflecting the data in the case of a cell connection failure state in anactual situation to reference data, reference data can be obtained moreprecisely.

3.5. Cell Connection Failure Detection Unit 500

The cell connection failure detection unit is configured to detectwhether a section matching the amount of change in the discharge voltagevalue due to the CID operation or the open parallel connection line fromthe actual driving discharge data monitored by the monitoring unit 300,and detect a cell connection failure state due to a CID operation of acorresponding battery or an open parallel connection line, and may beconfigured to include the following detailed configuration.

A. Match Comparison Unit 510

The match comparison unit may compare whether there is a sectionmatching the final connection failure detection reference data stored inthe memory unit 400 among actual driving discharge data of the batterymonitored by the monitoring unit 300.

In other words, from the amount of change (actual driving dischargedata) in the discharge voltage value of the battery currently beingdischarged derived as an analog signal in the form of a waveform asshown in FIG. 1, this is to compare whether there is a section matchingthe final connection failure detection reference data that occurs whenthe CID operates or the parallel connection line is opened.

B. Connection Failure Determination Unit 520

As a result of the comparison, if there is a section matching the finalconnection failure reference data in the actual driving discharge data,the corresponding section is detected as the area where the change inthe discharge voltage value is decreased due to the CID operation on thebattery or the open specific parallel line, it may be determined that acell connection failure occurs due to a CID operation or an openparallel connection line in the corresponding battery.

C. Cell Connection Failure Detection Signal Generation Unit 530

When the connection failure determination unit 520 determines that acell connection failure occurs due to a CID operation on the battery oran open specific parallel connection line, a cell connection failuredetection signal indicating this may be generated and outputted.

In addition, by feeding back data (failure detection data) about thechange amount of the discharge voltage value corresponding to thesection determined that the cell connection failure occurs due to theCID operation of the battery corresponding to the cell connectionfailure detection signal or the open parallel connection line to thememory unit 400 to reflect data in the case of a cell connection failurestate in an actual situation in the reference data previously stored inthe memory unit 400, it can be configured to secure reference data moreprecisely.

On the other hand, the cell connection failure detection signal mayinclude a battery identification number that can identify acorresponding battery in which a connection failure occurs due to a CIDoperation or an open parallel connection line, or a bank identificationnumber indicating a battery bank to which the battery belongs.

3.6. Notification Unit 600

When a cell connection failure detection signal is outputted from thecell connection failure detection signal generation unit 530, thenotification unit generates and outputs an abnormality signal includingthe battery identification number of the corresponding battery or thebank identification number that identifies the battery bank to which thebattery belongs, thereby allowing the user to recognize that a cellconnection failure state occurs due to CID operation or an open specificparallel line in the battery.

Meanwhile, the voltage measurement unit 200, the monitoring unit 300,the memory unit 400, and the cell connection failure detection unit 500are a control device or a control unit implementing the cell connectionfailure detection process described above of the present invention, andmay be configured to be integrated into one integrated microprocessor oran engine control electronic control unit (ECU) of the vehicle, and maybe configured to be integrated into the battery management device of thevehicle battery pack.

On the other hand, although the technical idea of the present inventionhas been specifically described according to the above embodiment, itshould be noted that the above embodiments are for the purpose ofexplanation and not limitation. In addition, those skilled in the art inthe technical field of the present invention will be able to understandthat various embodiments are possible within the scope of the spirit ofthe present invention.

1. A method of detecting connection failure of a parallel connectioncell, the method comprising: a reference data acquisition step ofacquiring reference data when a cell connection failure occurs bygenerating a current interruption device (CID) operation or a parallelconnection line open condition in a battery being discharged; amonitoring step of monitoring actual driving discharge data generated onthe battery being discharged by an operation of an external device; anda cell connection failure detection step of comparing, from an actualdriving discharge data monitored in the monitoring step, whether thereis a section matching the amount of change in a discharge voltage valueto the CID operation or the open parallel connection line in thereference data and detecting whether a cell connection failure occursdue to the CID operation or the open parallel connection line in thecorresponding battery according to a comparison result.
 2. The method ofclaim 1, further comprising an abnormality notification step ofgenerating and notifying an abnormality signal in response to it beingdetected that the battery is in a state in which cell connection failureoccurs due to the CID operation or the open parallel connection line inthe cell connection failure detection step.
 3. The method of claim 1,wherein the reference data acquisition step comprises: a drivingdischarge reference data acquisition step of measuring the dischargevoltage value at a predetermined periodic interval while discharging apredetermined reference battery connected to the external device throughan operation of the external device, and acquiring driving dischargereference data based on the measured discharge voltage value; aconnection failure time point reference data acquisition step ofacquiring connection failure time point reference data generatedaccordingly due to the CID operation or the open parallel connectionline at a predetermined time point while the driving discharge referencedata acquisition step is in progress; a first connection failuredetection data acquisition step of summing the acquired drivingdischarge reference data and connection failure time point referencedata for a same time interval and first acquiring data on a change inthe discharge voltage value in the CID operation or the open area of aparallel connection line; and a final connection failure detectionreference data acquisition step of repeating the driving dischargereference data acquisition step, the connection failure time pointreference data acquisition step, and the first connection failuredetection reference data acquisition step a predetermined number oftimes or more and by applying a machine learning technique to aplurality of first connection failure detection reference data obtainedthrough this, finally acquiring data on the amount of change in thedischarge voltage value in the CID operation or the parallel connectionline open area.
 4. The method of claim 3, wherein the cell connectionfailure detection step comprises: a match comparison step of comparingwhether the section matching the final connection failure detectionreference data acquired in the final connection failure detectionreference data acquisition step exists from the actual driving dischargedata monitored in the monitoring step; and a connection failuredetermination step of determining, from the actual driving dischargedata as a result of the match comparison step, the corresponding sectionas the section in which the amount of change in the discharge voltagevalue occurs due to the CID operation or the open parallel connectionline in response to there being the section matching the finalconnection failure detection reference data and determining that thecell connection failure occurs due to the CID operation or the openparallel connection line in the corresponding battery.
 5. The method ofclaim 3, wherein the driving discharge reference data is a change amountof the discharge voltage value for the reference battery, and whereinthe connection failure time point reference data is the change amount inthe discharge voltage value caused by the CID operation or the openparallel connection line with respect to the reference battery.
 6. Aconnection failure detection system of a parallel connection cell, thesystem comprising: one or more batteries including at least one or morecells connected in parallel; a voltage measurer configured to measure adischarge voltage of a battery at predetermined periodic intervals; amonitor configured to monitor actual driving discharge data derived asan analog signal in a waveform form based on the discharge voltage valuemeasured by the voltage measurer; a memory configured to store referencedata for detecting whether a cell connection failure occurs due to acurrent interruption device (CID) operation or an open parallelconnection line in the battery; and a cell connection failure detectorconfigured to detect whether there is a section matching the amount ofchange in the discharge voltage value due to the CID operation or theopen parallel connection line in the actual driving discharge datamonitored by the monitor using the reference data stored in the memoryand detect whether a cell connection failure occurs due to the CIDoperation or the open parallel connection line in the correspondingbattery.
 7. The system of claim 6, wherein the reference data stored inthe memory is configured to include final connection failure detectionreference data, and wherein the final connection failure detectionreference data is the amount of change in the discharge voltage value ofthe battery that occurs when the CID operates or the parallel connectionline is opened.
 8. The system of claim 7, wherein the cell connectionfailure detector comprises: a match comparator configured to comparewhether a section matching the final connection failure detection dataexists among actual driving discharge data of the battery monitored bythe monitor; a connection failure determiner configured to, as a resultof the comparison by the match comparator, determine the sectionmatching the final connection failure detection data in the actualdriving discharge data in which the amount of change in the dischargevoltage value occurs due to the CID operation or the open parallelconnection line open and determine whether a cell connection failureoccurs due to the CID operation or the open parallel connection lineopen in the corresponding battery; and a cell connection failuredetection signal generator configured to, in response to the connectionfailure determiner determining that the cell connection failure occursdue to the CID operation or the open parallel connection line in thecorresponding battery, generate and output a cell connection failuredetection signal.
 9. The system of claim 8, further comprising anotifier configured to generate and output an abnormality signal inresponse to a cell connection failure detection signal being output fromthe cell connection failure detection signal generator of the cellconnection failure detector.
 10. The system of claim 6, wherein theactual driving discharge data is the amount of change in the dischargevoltage value.